Start to look out for the first flowering of horse chestnut
full autumn tinting
When all the leaves on a tree have changed colour – full autumn colouring.
Use mature trees (30 years old or more), as young trees show different responses. Even trees of the same species, close to each other can behave very differently.
If you are finding it difficult to decide when to record, wait until the event is occurring in three trees of the same species in close proximity to each other. Record the trendsetters rather than the extraordinary.
In dry summers some species such as beech and birch may show the effects of drought, which can be confused with the onset of autumn.These include early colour changes and shrivelling and falling of leaves. Record the date you see first tint whatever the cause.